Many patients and their caregivers are apprehensive about CD screening in the context of T1D. For patients and families, diabetes is a challenging condition requiring daily efforts to balance meals, activity, and insulin to maintain adequate metabolic control. In adult diabetic patients, the presence of complications is associated with worsened quality of life [41
]. The impact of an additional chronic disease, such as CD, may substantially affect the quality of life in such patients, although research has not evaluated this question directly. Clinicians are also challenged by the fact that while screening tests are safe and effective, follow-up of positive serologic screens requires access to gastroenterologic consultation with invasive testing, as biopsy confirmation of intestinal damage remains the diagnostic gold standard. Lastly, maintaining a strict GFD in addition to a diabetic diet requires additional time, effort, and expense. It is not surprising that most T1D patients struggle with strict adherence to a GFD ().
Significant gaps exist in our understanding of the natural history of undiagnosed CD in T1D patients. We do not know if the outcomes of those identified by screening are similar to those who are clinically identified nor is it clear whether earlier identification, before the onset of clinical symptoms, impacts long-term outcome. Treatment options beyond a strict GFD, particularly for asymptomatic patients, must be explored as well. This would also benefit symptomatic patients who are not entirely compliant with a GFD. We also need to determine if a minimal threshold of gluten in the diet exists and is safe. In the long term, the impact of screening and treatment as they pertain to clinically relevant outcomes such as bone mineralization, diabetes control, and wellbeing are important questions worthy of study.
Despite these concerns, the prevalence of CD is higher in T1D: between 5–7-fold higher than the general population [34
]. Although some guidelines recommend that screening for CD should only in symptomatic T1D patients, many institutions, including ours, have embarked on screening programs as part of routine diabetic care. A proposed screening strategy with consideration of complication screening is outlined in . In our experience it is difficult to determine which patient is symptomatic, as most busy diabetes clinics do not routinely screen for many of the myriad of CD-related symptoms. But if clinicians overlook minor GI symptoms or ascribe them to complications of longstanding diabetes, a practice of routine testing may detect these symptomatic patients. From a medical perspective, numerous advantages may exist in screening asymptomatic patients with diabetes, including the potential of improved diabetic control and avoidance of long-term manifestations of CD. Impaired bone mineralization in adolescent patients with ongoing, unrecognized intestinal inflammation is of particular concern. Recent population-based and cohort studies examining adults with undiagnosed, serology positive CD had significant higher mortality than controls [11
], inferring that undiagnosed celiac disease is not a benign condition and questioning the ethics of asking or randomizing patients with CD not to pursue treatment.
Figure 1 Proposed Screening Schema for Patients At-risk for CD. *Low IgA levels may require additional testing of total immunoglobulins. **DXA scans should be considered for patients at baseline especially with positive evidence of familial osteoporosis, fracture (more ...)
The dilemma of screening for CD in T1D is complex. The classic CD presentation of a miserable, malnourished toddler is no longer typical, as patients who present are sometimes overweight and come from many ethnic groups. CD and T1D share common genetic origins and an increasing body of evidence identifies this intestinal insult as a provocative factor in the pathogenesis of T1D and other autoimmune conditions. For these reasons, it is important to emphasize to clinicians caring for pediatric patients that CD appears at a much higher rate in patients with diabetes and can present with multiple gastrointestinal and nonintestinal features. The challenge remains to follow the precept of primum non nocere: first do no harm in our approach to these patients and further evaluate the risks and benefits of screening relevant to clinically important outcomes.